This thread got me thinking about visiting secondary cities and how I somehow enjoy visiting secondary US cities - even the ones that are considered to be duds - while secondary European cities don't really entice me. For example, I'd rather visit Seattle over Stuttgart, Denver over Birmingham, St. Louis over Lille
Now, in a way this doesn't make any sense. The things I prize: a downtown that is the true commercial centre of the metropolis, vibrant, walkable neighbourhoods, a rich architectural history, etc. are far more prevalent in Stuttgart than in Denver. But I always felt that these secondary cities don't distinguish themselves too much from one another, or from their countries' respective alpha cities. So while visiting Berlin is one week of mind-blowing fun, Hannover deserves a two hour jaunt through the fussgängerzone between changing trains. NA cities don't fall into this trap as readily: sure, Miami and Houston and San Diego are all auto-centric sprawls but they offer a vastly different flavour in each case.
That said, I think you'll have a lot of fun in Edinburgh. Some European secondary cities are really so culturally distinct from other places that they warrant the trip: Edinburgh, Marseilles, Munich, Napoli, etc. are places like this.